Problem: The lifespans of gorillas in a particular zoo are normally distributed. The average gorilla lives $20.8$ years; the standard deviation is $3.1$ years. Use the empirical rule $(68-95-99.7\%)$ to estimate the probability of a gorilla living between $11.5$ and $27$ years.
Solution: The probability of a particular gorilla living between $11.5$ and $27$ years is ${2.35\%} + {95\%}$, or $97.35\%$.